Chill box



Dec. 13, 1966 M. w. STEVENS CHILL BOX Filed Sept. 30, "1963 FiG.H

INVENTOR. LL W. STEVENS United States Patent Office 3,291,469 Patented Dec. 13, 1966 3,291,469 CHILL BOX Marshall W. Stevens, Long Hill, Conn., assignor to The Bullard Company, Bridgeport, Conn., a corporation of Connecticut Filed Sept. 30, 1963, Ser. No. 312,396 1 Claim. (Cl. 266-6) This invention relates to the art of casting metal, and particularly to an improved chill box for chilling test specimens of cast iron to determine visually the condition of the melt.

In the making of cast iron, the cupola is charged with successive layers of ingredients that make up the charge. These charges produce various grades of cast iron depending upon the ingredients.

In general, there are two things that can happen to the large amount of carbon in cast iron. Either it separates in particles of graphite to form gray iron, or it combines with iron or an alloy to form the hard, brittle carbides of white iron.

The tendency of the carbon in cast iron to form hard and brittle carbides, instead of graphite, is what is shown by the chill test. The depth of white iron in the fracture of a rapidly cooled gray iron test specimen is a measure of hardness and brittleness.

When the molten iron is drawn off, the operator requires a quick visual indication of the amount of hard, brittle carbides, such as Fe C, present in the melt. The amount of Fe C present in a melt can be visually determined since it is proportional to the rate of chilling of a cast specimen through the lower transformation temperature of about 1333 F. Accordingly, it is common practice to cast test specimens of small size, usually of triangular cross section, and when they become solid at about 2066 F., they are chilled in water and transversely fractured to determine visually the amount of Fe C present in the melt. The Fe C imparts a silver sheen in contrast to the dull gray of the remainder of the specimen, and steps can be taken to increase or decrease the amount of Fe C if the visual indication is substantially accurate and observed soon enough.

After the foundryman has gained some experience in the use of the test and has correlated chill depth with hardness, composition and machinability, he will be able to tell quickly whether his iron is suitable for pouring. If the iron is not right, necessary adjustments can be made by means of ladle additions. For instance, silicon may be added to graphitize light sections, and chromium may be added to increase hardness or give better structure in heavy sections. Most alloys have a decided effect on the depth of chill, and the chill test is frequently used in controlling the proper amount of alloy addition.

Should the rate of chill vary substantially, the indication of the amount of Fe C present in the melt will be erroneous.

The principal object of the invention is to provide apparatus for ensuring a substantially constant chilling rate of test specimens of cast iron so as to ensure a substantially accurate visual indication of the amount of Fe C present in the melt.

Another object of the invention is to provide such an apparatus in which a portion of the test specimen is continuously subjected to water at substantially the same temperature.

Still another object of the invention is to provide a portable chill box of compact design.

In one aspect of the invention, a chill box may be composed of a main housing having two side walls, two end walls, a top wall and a bottom wall, there being an inlet near the center of one end wall and an outlet near the bottom of an end wall.

In another aspect of the invention, a cylindrical inner housing may extend from one end wall to the other. There may be elongated, axially extending opening in the top of the cylindrical inner housing that is aligned with a similar elongated opening in the top wall of the main housing.

In still another aspect of the invention, axially aligned supports may extend from each end wall within the elongated opening in the cylindrical housing toward each other for supporting an elongated, triangular cross sec tion cast test specimen on its base portion and such that its base portion lies substantially at the top of the elongated opening in the cylindrical housing.

The construction is such that with water continuously flowing into and out of the inlet and outlet, the base of a cast test specimen supported in the openings of said box is subjected to a substantially constant chilling rate by the continuous flow of water over it.

The above, other objects and novel features of the chill box will become apparent from the following specifi cation and accompanying drawing which are merely exemplary.

In the drawing:

FIG. 1 is an elevational view, partly in section, of a chill box to which the principles of the invention have been applied; and

FIG. 2 is a sectional view taken substantially along line 2-2 of FIG. 1.

Referring to the drawing, the principles of the invention are shown as applied to a chill box including a main housing 10 including side walls 11, 12, a bottom wall 13, and a top wall 14. End walls 15 and 16 complete the frame of housing 10. An elongated opening 17 is formed axially along the top wall 14 of housing 10.

An inner cylindrical housing 18 extends from one end wall 15 to the other end wall 16, forming a joint therewith and dividing the housing 10 into an inner chamber 19 and an outer chamber 20. An elongated opening 21 may extend axially along the top of the cylindrical housing 18 and it may be aligned with the opening 17 in top wall 14. There may be a flange 22 surrounding the opening 21, and it may be spaced slightly downwardly from the inner surface of the top wall 14.

Aligned brackets 23, 24 may extend toward each other from the inner surfaces of the end walls 15 and 16 for supporting a cast test specimen 25 on its base 26. The specimen may be of triangular cross section. An inlet 27 may admit water to the inner chamber 19, filling it and spilling over the top edge of the flange 22, passing out through an outlet 28 in the lower portion of end wall 16. The elevation of the brackets 23, 24 is such that the base of the specimen 25 is in contact with a constant flow of water at substantially the same tempera ture. Accordingly, the chilling of the specimen can be regulated to provide a substantially uniform chill rate, thereby to ensure a substantailly accurate visual determination of the amount of Fe C in the melt being tested.

Although the various features of the improved chill box have been shown and described in detail to fully disclose one embodiment of the invention, it will be evident that changes may be made in such details and certain features may be used without others without departing from the principles of the invention.

What is claimed is:

A chill box for chilling at a substantially uniform rate the bottom portion of a cast iron test specimen, comprising an outer housing having an upper wall portion; an inner housing having an upper wall portion disposed within said outer housing and cooperatively forming therewith separate inner and outer chambers within said outer housing; an opening in the upper wall portion of said inner housing having a horizontally disposed upper surface spaced vertically downwardly from an aligned opening in the upper wall portion of said outer housing to provide a flow path from said inner chamber to said outer chamber within said outer housing; means disposed within said outer housing for supporting a test specimen with the bottom portion thereof disposed entirely over said opening in the upper wall portion of said inner housing and adjacent said flow path and with a lowermost surface of said bottom portion disposed substantially on a level with said horizontally disposed surface; and means for chilling said bottom portion at a substantially uniform rate by directing a substantially constant flow of liquid past said bottom portion and along said flow path, said chilling means including means for introducing cooling References Cited by the Examiner UNITED STATES PATENTS 7/1939 Ferngren 118-429 1/1964 Rieben 22837 10 JOHN F. CAMPBELL, Primary Examiner.

WHITMORE A. WILTZ, Examiner.

M. L. FAIGUS, Assistant Examiner. 

